Classic Album recommendations

My dad is really getting into the blues lately so I want to buy him a really good album. I'm not that familiar with the blues (I know, shame on me!) and that's why I'm asking your help.What are some really good (and not to rare) albums?

Bluesbreakers - John Mayall and Eric ClaptonHard Again - Muddy WatersAmerican Axe Live in 1974 - Roy Buchanon (Might be difficult to find, but it's an amazing album)Getting Ready - Freddie KingRiding With The King - B.B. King and Eric Clapton

I think you should know what songs he currently likes, so that we give you something that's in the range of liking of what he is listening to. I personally like minor blues, and major usually pisses me off (and yet... and yet...).

But in my opinion, raw blues by jimi hendrix is one of the best blues albums on this earth, it has covers and other stuff, and contains a sh*tload of songs, it has a nice variety of blues songs, although most of them are in minor. Stalk your dad's computer to figure out what he's been listening to.

Freddie King - BurglarB.B. King - Live Album Trilogy (Live at The Regal, Live at Cook County Jail, Blues Is King) Robert Johnson - King Of The Delta Blues/Complete RecordingsAlbert King - Born Under A Bad SignHowlin' Wolf - Moaning at Midnight.